In vivo evaluation of human patellar tendon microstructure and microcirculation with diffusion MRI. Issue 3 (12th August 2019)

• Record Type: Journal Article
• Authors: Wengler, Kenneth; Fukuda, Takeshi; Tank, Dharmesh; Komatsu, David E.; Paulus, Megan; Huang, Mingqian; Gould, Elaine S.; Schweitzer, Mark E.; He, Xiang
• Is Part Of: Journal of magnetic resonance imaging. Volume 51:Issue 3(2020)
• Page Start: 780
• Page End: 790
• Publication Date: 2019-08-12
• Subjects: patellar tendon -- DTI -- IVIM -- microcirculation -- microstructure; Magnetic resonance imaging -- Periodicals; 616
• DOI: 10.1002/jmri.26898
• Languages: English
• ISSNs: 1053-1807

Abstract

Abstract : Background: Patellar tendon (PT) microstructure integrity and microcirculation status play a crucial role in the progression of tendinopathy and tendon repair. Purpose: To assess the feasibility and robustness of stimulated‐echo based diffusion‐weighted MRI with readout‐segmented echo‐planar imaging (ste‐RS‐EPI) for noninvasive assessment of microstructure and microcirculation of human PT. Study Type: Prospective. Subjects: Fifteen healthy volunteers. Field Strength/Sequence: PT diffusion tensor imaging (DTI) and intravoxel incoherent motion (IVIM) were acquired with an ste‐RS‐EPI protocol on a 3T MRI scanner. Assessment: Subjects were positioned with their PT at the magic angle. DTI‐derived parameters including axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), and fractional anisotropy (FA) were estimated with b ‐values of 0 and 800 s/mm 2 and 12 diffusion directions. IVIM‐derived parameters, f p, D* × f p, V b, and D* × V b were assessed in the central‐third and the outer‐two thirds of the PT with b ‐values of 0, 20, 30, 60, 80, 120, 200, 400, and 600 s/mm 2 in three orthogonal directions. Statistical Tests: Paired t ‐tests were used to evaluate differences in IVIM parameters between the central‐third and outer‐two thirds regions of the patellar tendon. Paired t ‐tests and within‐subject coefficient of variation were used to assess the intra‐ and intersession reproducibility of PT DTI and IVIM parameters. Results: DTI parameters for healthy PT were 1.54 ± 0.09 × 10 ‐3 mm 2 /s, 1.01 ± 0.05 × 10 ‐3 mm 2 /s, 1.18 ± 0.06 × 10 ‐3 mm 2 /s, and 0.30 ± 0.04 for AD, RD, MD, and FA, respectively. Significantly higher ( P < 0.05) IVIM parameters f p and D* × f p were observed in the outer‐two thirds (6.1% ± 2.4% and 95.2 ± 49.6, respectively) compared with the central‐third (3.8% ± 2.3% and 48.6 ± 35.2, respectively) of the PT. Data Conclusion: Diffusion MRI of PT with an ste‐RS‐EPI protocol is clinically feasible. Both DTI‐ and IVIM‐derived parameters of the PT demonstrated good test–retest reproducibility and interrater reliability. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:780–790.